Errors by a former federal official took land from the threatened species. Its habitat may be restored.

The U.S. Fish and Wildlife Service proposed on Tuesday to more than triple the habitat set aside for the threatened frog, citing scientific miscalculations and political manipulation by former Interior Department official Julie MacDonald that had greatly reduced the protected acreage.

MacDonald resigned in May 2007 after an internal investigation showed she had altered scientific conclusions to reduce protections for endangered species and had provided internal documents to lobbyists. Since then, the department has been reconsidering eight decisions made while MacDonald oversaw the endangered species program for the U.S. Fish and Wildlife Service, part of the Interior Department.

Tuesday's decision, a result of that review, would create a 1.8-million-acre habitat in 28 Central and Northern California counties. Development and destruction of wetlands have eliminated the frogs from more than 70% of their historic range. MacDonald would have reduced what was left of the frog's range by 82%.

An Interior Department investigation found that MacDonald pressured staff to count three sub-species of the California tiger salamander as one, which undermined the case for protection. A federal judge overturned that decision in 2005, saying it was made "without even a semblance of agency reasoning."

The investigation determined that MacDonald improperly provided department information to lobbyists and private-sector interests, such as the California Farm Bureau and the Building Industry Assn. of Southern California.

"MacDonald appears to have a close personal and business relationship with a Farm Bureau lobbyist," the report said.

The public will have 60 days to comment on the proposed habitat. The agency will undertake an economic analysis to determine if the financial burden on property owners from habitat protections is outweighed by any benefit to species.

The Fish and Wildlife Service previously released a study that showed nearly $500 million in costs to home builders for protecting the frog's habitat.